--- Useful functions for getting directory contents and matching them against wildcards.
-- @class module
-- @name pl.dir

local utils = require 'pl.utils'
local path = require 'pl.path'
local is_windows = path.is_windows
local tablex = require 'pl.tablex'
local ldir = path.dir
local chdir = path.chdir
local mkdir = path.mkdir
local rmdir = path.rmdir
local sub = string.sub
local os,pcall,ipairs,pairs,require,setmetatable,_G = os,pcall,ipairs,pairs,require,setmetatable,_G
local remove = os.remove
local append = table.insert
local wrap = coroutine.wrap
local yield = coroutine.yield
local assert_arg,assert_string,raise = utils.assert_arg,utils.assert_string,utils.raise
local List = utils.stdmt.List

--[[
module ('pl.dir',utils._module)
]]

local dir = {}

local function assert_dir (n,val)
    assert_arg(n,val,'string',path.isdir,'not a directory')
end

local function assert_file (n,val)
    assert_arg(n,val,'string',path.isfile,'not a file')
end

local function filemask(mask)
    mask = utils.escape(mask)
    return mask:gsub('%%%*','.+'):gsub('%%%?','.')..'$'
end

--- does the filename match the shell pattern?.
-- (cf. fnmatch.fnmatch in Python, 11.8)
-- @param file A file name
-- @param pattern A shell pattern
-- @return true or false
-- @raise file and pattern must be strings
function dir.fnmatch(file,pattern)
    assert_string(1,file)
    assert_string(2,pattern)
    return path.normcase(file):find(filemask(pattern)) ~= nil
end

--- return a list of all files which match the pattern.
-- (cf. fnmatch.filter in Python, 11.8)
-- @param files A table containing file names
-- @param pattern A shell pattern.
-- @return list of files
-- @raise file and pattern must be strings
function dir.filter(files,pattern)
    assert_arg(1,files,'table')
    assert_string(2,pattern)
    local res = {}
    local mask = filemask(pattern)
    for i,f in ipairs(files) do
        if f:find(mask) then append(res,f) end
    end
    return setmetatable(res,List)
end

local function _listfiles(dir,filemode,match)
    local res = {}
    local check = utils.choose(filemode,path.isfile,path.isdir)
    if not dir then dir = '.' end
    for f in ldir(dir) do
        if f ~= '.' and f ~= '..' then
            local p = path.join(dir,f)
            if check(p) and (not match or match(p)) then
                append(res,p)
            end
        end
    end
    return setmetatable(res,List)
end

--- return a list of all files in a directory which match the a shell pattern.
-- @param dir A directory. If not given, all files in current directory are returned.
-- @param mask  A shell pattern. If  not given, all files are returned.
-- @return lsit of files
-- @raise dir and mask must be strings
function dir.getfiles(dir,mask)
    assert_dir(1,dir)
    assert_string(2,mask)
    local match
    if mask then
        mask = filemask(mask)
        match = function(f)
            return f:find(mask)
        end
    end
    return _listfiles(dir,true,match)
end

--- return a list of all subdirectories of the directory.
-- @param dir A directory
-- @return a list of directories
-- @raise dir must be a string
function dir.getdirectories(dir)
    assert_dir(1,dir)
    return _listfiles(dir,false)
end

local function quote_argument (f)
    f = path.normcase(f)
    if f:find '%s' then
        return '"'..f..'"'
    else
        return f
    end
end


local alien,ffi,ffi_checked,CopyFile,MoveFile,GetLastError,win32_errors,cmd_tmpfile

local function execute_command(cmd,parms)
   if not cmd_tmpfile then cmd_tmpfile = path.tmpname () end
   local err = path.is_windows and ' > ' or ' 2> '
    cmd = cmd..' '..parms..err..cmd_tmpfile
    local ret = utils.execute(cmd)
    if not ret then
        return false,(utils.readfile(cmd_tmpfile):gsub('\n(.*)',''))
    else
        return true
    end
end

local function find_ffi_copyfile ()
    if not ffi_checked then
        ffi_checked = true
        local res
        res,alien = pcall(require,'alien')
        if not res then
            alien = nil
            res, ffi = pcall(require,'ffi')
        end
        if not res then
            ffi = nil
            return
        end
    else
        return
    end
    if alien then
        -- register the Win32 CopyFile and MoveFile functions
        local kernel = alien.load('kernel32.dll')
        CopyFile = kernel.CopyFileA
        CopyFile:types{'string','string','int',ret='int',abi='stdcall'}
        MoveFile = kernel.MoveFileA
        MoveFile:types{'string','string',ret='int',abi='stdcall'}
        GetLastError = kernel.GetLastError
        GetLastError:types{ret ='int', abi='stdcall'}
    elseif ffi then
        ffi.cdef [[
            int CopyFileA(const char *src, const char *dest, int iovr);
            int MoveFileA(const char *src, const char *dest);
            int GetLastError();
        ]]
        CopyFile = ffi.C.CopyFileA
        MoveFile = ffi.C.MoveFileA
        GetLastError = ffi.C.GetLastError
    end
    win32_errors = {
        ERROR_FILE_NOT_FOUND    =         2,
        ERROR_PATH_NOT_FOUND    =         3,
        ERROR_ACCESS_DENIED    =          5,
        ERROR_WRITE_PROTECT    =          19,
        ERROR_BAD_UNIT         =          20,
        ERROR_NOT_READY        =          21,
        ERROR_WRITE_FAULT      =          29,
        ERROR_READ_FAULT       =          30,
        ERROR_SHARING_VIOLATION =         32,
        ERROR_LOCK_VIOLATION    =         33,
        ERROR_HANDLE_DISK_FULL  =         39,
        ERROR_BAD_NETPATH       =         53,
        ERROR_NETWORK_BUSY      =         54,
        ERROR_DEV_NOT_EXIST     =         55,
        ERROR_FILE_EXISTS       =         80,
        ERROR_OPEN_FAILED       =         110,
        ERROR_INVALID_NAME      =         123,
        ERROR_BAD_PATHNAME      =         161,
        ERROR_ALREADY_EXISTS    =         183,
    }
end

local function two_arguments (f1,f2)
    return quote_argument(f1)..' '..quote_argument(f2)
end

local function file_op (is_copy,src,dest,flag)
    if flag == 1 and path.exists(dest) then
        return false,"cannot overwrite destination"
    end
    if is_windows then
        -- if we haven't tried to load Alien/LuaJIT FFI before, then do so
        find_ffi_copyfile()
        -- fallback if there's no Alien, just use DOS commands *shudder*
        -- 'rename' involves a copy and then deleting the source.
        if not CopyFile then
            src = path.normcase(src)
            dest = path.normcase(dest)
            local cmd = is_copy and 'copy' or 'rename'
            local res, err = execute_command('copy',two_arguments(src,dest))
            if not res then return nil,err end
            if not is_copy then
                return execute_command('del',quote_argument(src))
            end
        else
            if path.isdir(dest) then
                dest = path.join(dest,path.basename(src))
            end
			local ret
            if is_copy then ret = CopyFile(src,dest,flag)
            else ret = MoveFile(src,dest) end
            if ret == 0 then
                local err = GetLastError()
                for name,value in pairs(win32_errors) do
                    if value == err then return false,name end
                end
                return false,"Error #"..err
            else return true
            end
        end
    else -- for Unix, just use cp for now
        return execute_command(is_copy and 'cp' or 'mv',
            two_arguments(src,dest))
    end
end

--- copy a file.
-- @param src source file
-- @param dest destination file or directory
-- @param flag true if you want to force the copy (default)
-- @return true if operation succeeded
-- @raise src and dest must be strings
function dir.copyfile (src,dest,flag)
    assert_string(1,src)
    assert_string(2,dest)
    flag = flag==nil or flag
    return file_op(true,src,dest,flag and 0 or 1)
end

--- move a file.
-- @param src source file
-- @param dest destination file or directory
-- @return true if operation succeeded
-- @raise src and dest must be strings
function dir.movefile (src,dest)
    assert_string(1,src)
    assert_string(2,dest)
    return file_op(false,src,dest,0)
end

local function _dirfiles(dir,attrib)
    local dirs = {}
    local files = {}
    for f in ldir(dir) do
        if f ~= '.' and f ~= '..' then
            local p = path.join(dir,f)
            local mode = attrib(p,'mode')
            if mode=='directory' then
                append(dirs,f)
            else
                append(files,f)
            end
        end
    end
    return setmetatable(dirs,List),setmetatable(files,List)
end


local function _walker(root,bottom_up,attrib)
    local dirs,files = _dirfiles(root,attrib)
    if not bottom_up then yield(root,dirs,files) end
    for i,d in ipairs(dirs) do
        _walker(root..path.sep..d,bottom_up,attrib)
    end
    if bottom_up then yield(root,dirs,files) end
end

--- return an iterator which walks through a directory tree starting at root.
-- The iterator returns (root,dirs,files)
-- Note that dirs and files are lists of names (i.e. you must say path.join(root,d)
-- to get the actual full path)
-- If bottom_up is false (or not present), then the entries at the current level are returned
-- before we go deeper. This means that you can modify the returned list of directories before
-- continuing.
-- This is a clone of os.walk from the Python libraries.
-- @param root A starting directory
-- @param bottom_up False if we start listing entries immediately.
-- @param follow_links follow symbolic links
-- @return an iterator returning root,dirs,files
-- @raise root must be a string
function dir.walk(root,bottom_up,follow_links)
    assert_string(1,root)
    if not path.isdir(root) then return raise 'not a directory' end
    local attrib
    if path.is_windows or not follow_links then
        attrib = path.attrib
    else
        attrib = path.link_attrib
    end
    return wrap(function () _walker(root,bottom_up,attrib) end)
end

--- remove a whole directory tree.
-- @param fullpath A directory path
-- @return true or nil
-- @return error if failed
-- @raise fullpath must be a string
function dir.rmtree(fullpath)
    assert_string(1,fullpath)
    if not path.isdir(fullpath) then return raise 'not a directory' end
    if path.islink(fullpath) then return false,'will not follow symlink' end
    for root,dirs,files in dir.walk(fullpath,true) do
        for i,f in ipairs(files) do
            remove(path.join(root,f))
        end
        rmdir(root)
    end
    return true
end

local dirpat
if path.is_windows then
    dirpat = '(.+)\\[^\\]+$'
else
    dirpat = '(.+)/[^/]+$'
end

local _makepath
function _makepath(p)
    -- windows root drive case
    if p:find '^%a:[\\]*$' then
        return true
    end
   if not path.isdir(p) then
    local subp = p:match(dirpat)
    if not _makepath(subp) then return raise ('cannot create '..subp) end
    return mkdir(p)
   else
    return true
   end
end

--- create a directory path.
-- This will create subdirectories as necessary!
-- @param p A directory path
-- @return a valid created path
-- @raise p must be a string
function dir.makepath (p)
    assert_string(1,p)
    return _makepath(path.normcase(path.abspath(p)))
end


--- clone a directory tree. Will always try to create a new directory structure
-- if necessary.
-- @param path1 the base path of the source tree
-- @param path2 the new base path for the destination
-- @param file_fun an optional function to apply on all files
-- @param verbose an optional boolean to control the verbosity of the output.
--  It can also be a logging function that behaves like print()
-- @return true, or nil
-- @return error message, or list of failed directory creations
-- @return list of failed file operations
-- @raise path1 and path2 must be strings
-- @usage clonetree('.','../backup',copyfile)
function dir.clonetree (path1,path2,file_fun,verbose)
    assert_string(1,path1)
    assert_string(2,path2)
    if verbose == true then verbose = print end
    local abspath,normcase,isdir,join = path.abspath,path.normcase,path.isdir,path.join
    local faildirs,failfiles = {},{}
    if not isdir(path1) then return raise 'source is not a valid directory' end
    path1 = abspath(normcase(path1))
    path2 = abspath(normcase(path2))
    if verbose then verbose('normalized:',path1,path2) end
    -- particularly NB that the new path isn't fully contained in the old path
    if path1 == path2 then return raise "paths are the same" end
    local i1,i2 = path2:find(path1,1,true)
    if i2 == #path1 and path2:sub(i2+1,i2+1) == path.sep then
        return raise 'destination is a subdirectory of the source'
    end
    local cp = path.common_prefix (path1,path2)
    local idx = #cp
    if idx == 0 then -- no common path, but watch out for Windows paths!
        if path1:sub(2,2) == ':' then idx = 3 end
    end
    for root,dirs,files in dir.walk(path1) do
        local opath = path2..root:sub(idx)
        if verbose then verbose('paths:',opath,root) end
        if not isdir(opath) then
            local ret = dir.makepath(opath)
            if not ret then append(faildirs,opath) end
            if verbose then verbose('creating:',opath,ret) end
        end
        if file_fun then
            for i,f in ipairs(files) do
                local p1 = join(root,f)
                local p2 = join(opath,f)
                local ret = file_fun(p1,p2)
                if not ret then append(failfiles,p2) end
                if verbose then
                    verbose('files:',p1,p2,ret)
                end
            end
        end
    end
    return true,faildirs,failfiles
end

--- return an iterator over all entries in a directory tree
-- @param d a directory
-- @return an iterator giving pathname and mode (true for dir, false otherwise)
-- @raise d must be a non-empty string
function dir.dirtree( d )
    assert( d and d ~= "", "directory parameter is missing or empty" )
    local exists, isdir = path.exists, path.isdir
    local sep = path.sep

    local last = sub ( d, -1 )
    if last == sep or last == '/' then
        d = sub( d, 1, -2 )
    end

    local function yieldtree( dir )
        for entry in ldir( dir ) do
            if entry ~= "." and entry ~= ".." then
                entry = dir .. sep .. entry
                if exists(entry) then  -- Just in case a symlink is broken.
                    local is_dir = isdir(entry)
                    yield( entry, is_dir )
                    if is_dir then
                        yieldtree( entry )
                    end
                end
            end
        end
    end

    return wrap( function() yieldtree( d ) end )
end


---	Recursively returns all the file starting at <i>path</i>. It can optionally take a shell pattern and
--	only returns files that match <i>pattern</i>. If a pattern is given it will do a case insensitive search.
--	@param start_path {string} A directory. If not given, all files in current directory are returned.
--	@param pattern {string} A shell pattern. If not given, all files are returned.
--	@return Table containing all the files found recursively starting at <i>path</i> and filtered by <i>pattern</i>.
--  @raise start_path must be a string
function dir.getallfiles( start_path, pattern )
    assert( type( start_path ) == "string", "bad argument #1 to 'GetAllFiles' (Expected string but recieved " .. type( start_path ) .. ")" )
    pattern = pattern or ""

    local files = {}
    local normcase = path.normcase
    for filename, mode in dir.dirtree( start_path ) do
        if not mode then
            local mask = filemask( pattern )
            if normcase(filename):find( mask ) then
                files[#files + 1] = filename
            end
        end
    end

    return files
end

return dir